The present invention relates to a navigation device installed in a vehicle.
In recent years, the kinds and the quantities of various pieces of information for supporting a driving operation, which are provided to a user such as a driver in accordance with the change of surroundings around a vehicle, have been rapidly increasing. For example, in addition to vehicle information such as traveling speed, traveling distance, arbitrary interval distance, fuel residual quantity, cooling water temperature, and the like, there is navigation information for displaying a present position or an object point on a map, or road traffic information transmitted through electric wave signals. For the purpose of effectively transmitting lots of such information to the user, as shown in FIG. 3, a vehicle display device 100 is proposed in which an information display unit 30, such as a liquid crystal panel, capable of displaying an image is incorporated together with pointer drive units 10 and 20 each of which points a value by rotation movement of a pointer on a dial plate (for example, see Japanese Patent Unexamined Publication No. Hei. 11-240355). Incidentally, reference numeral 40 designates a digital display unit which is made of a display element, such as a fluorescent display tube, enabling a numerical display and displays the traveling distance and the interval distance.
That is, the vehicle display device 100 is structured such that the pointer drive units 10 and 20 and the digital display unit 40 display the vehicle information, and the information display unit 30 displays the road traffic information.
By this, since the user can instantaneously confirm the plural pieces of information such as the vehicle information and the road traffic information in the one vehicle display device 100, it is convenient.
In a recent navigation device, a so-called hybrid type one is dominant. This is such that the position data of the present place calculated by a not-shown navigation unit receiving an electric wave from a GPS satellite and the distance data of a traveling distance from a start point, which is calculated by a control device of the vehicle display device 100 on the basis of pulse signals outputted from not-shown sensor portions set at respective portions of the vehicle and corresponding to the traveling of the vehicle, are collectively used and the present position of the vehicle is obtained by a control device of the navigation unit.
Thus, the navigation unit must receive the distance data every certain time (for example, several hundred milliseconds), and if this input stops, accurate position calculation is not performed, and there occurs such a disadvantage that the renewal of the display on the display device 30 is delayed.
The present invention includes a sensor which outputs a pulse signal corresponding to a traveling distance of a vehicle, a vehicle display device which displays, based on the pulse signal, vehicle information including the traveling distance, and a navigation unit which receives distance data related to the traveling distance, obtained by processing the pulse signal, being outputted from the vehicle display device or the pulse signal at a certain reception period to calculate a present position of the vehicle, and controls the vehicle display device to display road traffic information including a display synthesized with the present position on a map on the basis of map data read from a map information memory medium, and is characterized in that in the case where the navigation unit can not receive the distance data or the pulse signal within the reception period, an estimated value of a value to be received this time is obtained from a variation between a value inputted last time and a value inputted last time but one, and the navigation unit calculates the present position on the basis of the estimated value. By carrying out the estimate processing, the navigation unit can temporarily obtain the distance data or the pulse signal at the certain reception period, so that deterioration of the display, such as non-renewal of the display, can be suppressed.
Besides, the invention includes a sensor which outputs a pulse signal corresponding to a traveling distance of a vehicle, a vehicle display device which displays, based on the pulse signal, vehicle information including the traveling distance, and a navigation unit which receives distance data related to the traveling distance, obtained by processing the pulse signal, being outputted from the vehicle display device or the pulse signal at a certain reception period to calculate a present position of the vehicle, and controls the vehicle display device to display road traffic information including a display synthesized with the present position on a map on the basis of map data read from a map information memory medium, and is characterized in that in the case where the navigation unit can not receive the distance data or the pulse signal within the reception period, an estimated value of a value to be received this time is obtained from a variation between a value inputted last time and a value inputted last time but one, the navigation unit calculates the present position on the basis of the estimated value, and an error contained in the estimated value is calculated and corrected from a value to be properly received in future and the estimated value. By carrying out the estimate processing, the navigation unit can temporarily obtain the distance data or the pulse signal at the certain reception period, so that deterioration of the display, such as non-renewal of the display, can be suppressed.
Besides, there is a feature that a serial communication line for transferring the estimated value obtained by the vehicle display device to the navigation unit is connected between the vehicle display device and the navigation unit, and even in a structure in which the distance data or the pulse signal is transferred through the serial communication having a low communication speed, by carrying out the estimate processing, the navigation unit can temporarily obtain the distance data or the pulse signal at the certain reception period, so that deterioration of the display, such as non-renewal of the display, can be suppressed.
Besides, there is a feature that the navigation unit has a built-in control device for obtaining the estimated value by the navigation unit, and the control device for obtaining the estimated value can be also used for a control device for controlling the navigation unit, and in this case, cost reduction by the common use of parts can be realized.
Besides, the invention includes a sensor which outputs a pulse signal corresponding to a traveling distance of a vehicle, a vehicle display device which displays, based on the pulse signal, vehicle information including the traveling distance, and a navigation unit which receives distance data related to the traveling distance, obtained by processing the pulse signal, being outputted from the vehicle display device at a certain reception period to calculate a present position of the vehicle, and controls the vehicle display device to display road traffic information including a display synthesized with the present position on a map on the basis of map data read from a map information memory medium, and is characterized in that the distance sensor and the vehicle display device are connected to a bus wired to be drawn around in an inside of the vehicle, the vehicle display device and the navigation unit are connected to each other through a serial communication line, and in the case where the navigation unit can not receive the distance data within the reception period, an estimated value of a value to be received this time is obtained from a variation between a value inputted last time and a value inputted last time but one, and the navigation unit calculates the present position on the basis of the estimated value. By carrying out the estimate processing, the navigation unit can temporarily obtain the distance data at the certain reception period, so that deterioration of the display, such as non-renewal of the display, can be suppressed.
Besides, the invention includes a sensor which outputs a pulse signal corresponding to a traveling distance of a vehicle, a vehicle display device which displays, based on the pulse signal, vehicle information including the traveling distance, and a navigation unit which receives distance data related to the traveling distance, obtained by processing the pulse signal, being outputted from the vehicle display device at a certain reception period to calculate a present position of the vehicle, and controls the vehicle display device to display road traffic information including a display synthesized with the present position on a map on the basis of map data read from a map information memory medium, and is characterized in that the distance sensor and the vehicle display device are connected to a bus wired to be drawn around in an inside of the vehicle, the vehicle display device and the navigation unit are connected to each other through a serial communication line, and in the case where the navigation unit can not receive the distance data within the reception period, an estimated value of a value to be received this time is obtained from a variation between a value inputted last time and a value inputted last time but one, the navigation unit calculates the present position on the basis of the estimated value, and an error contained in the estimated value is calculated and corrected from a value to be properly received in future and the estimated value. By carrying out the estimate processing, the navigation unit can temporarily obtain the distance data at the-certain reception period, so that deterioration of the display, such as non-renewal of the display, can be suppressed.